1. Field of the Invention:
The present invention relates to an automatic spraying method wherein the distance between a spray apparatus and an object is continuously detected, and the position of a valve member of a control valve means for controlling the flow rate of a fluid to be jetted out is varied in accordance with the detected distance.
2. Description of the Related Art:
A means has already been known wherein the position of a valve member of a control valve means for controlling the flow rate of a fluid to be jetted out is automatically varied in accordance with the distance between a spray apparatus and an object (said distance being hereinafter referred to as "spray distance") in order to maintain a desired coating thickness (or a desired spray pattern in addition thereto) even when the spray distance changes. However, since the spray distance and the amount of displacement of the valve member are not linearly related to each other, it has heretofore been necessary to obtain a complicated curve representing the relationship therebetween by carrying out experiments in advance, and then to program the obtained relationship into a microcomputer so that, when data representing a particular spray distance is input, it is possible to obtain data representing the amount of displacement of the valve member which corresponds to the spray distance input. Such experimentation and programming take an unfavorably long time, and the microcomputer needs to have an inconveniently large capacity.